AI tax research for Claude & ChatGPT
TaxMCP adds source-linked tax research to Claude and ChatGPT. Ask a question, retrieve the primary authority behind the answer, and open the source your reviewer needs to verify it.
What are the requirements for the home office deduction?
Under §280A, a home office deduction requires the space to be used:
What about the simplified method?
Works inside the AI tools you already use
The Problem
General AI can produce confident tax answers without a source you can inspect. Standalone research platforms add another interface, another subscription, and another workflow. TaxMCP gives the assistant you already use a direct path to primary authority.
Connect TaxMCP, ask a real research question, and inspect the returned authority before paying for a firm-wide rollout. The free plan includes 20 searches per day.
ChatGPT and Claude can still make analytical mistakes. Retrieved sections and rulings give the reviewer a real source to open instead of another unsupported assertion to audit.
TaxMCP retrieves public tax authority and does not require a client return or supporting documents. Research abstract or de-identified facts while keeping your firm's data-handling policy in control.
The Proof
Without taxmcp.io, a leading AI model sounds authoritative on tax. It's right often enough that the wrong answers slip through into client work. We put the same stratified set of U.S. federal tax questions to it twice: once on its own, once connected to taxmcp.io, with every answer independently graded against primary authority. Same model, same questions; the only variable was access to the source.1
on recent-law questions1
a failing 4.8 without taxmcp.io
free of critical errors1
1 in 3 carried one without taxmcp.io
exact figures & dates correct1
vs 89.6% without taxmcp.io
overall accuracy grade1
up from 7.4 without taxmcp.io
Right or tied on 93% of questions1, and every answer grounded in the Internal Revenue Code, Treasury Regs, IRS Publications & rulings, with a verifiable link.
Three real benchmark questions, graded 0–10. Average lift across the full set: +2.43.
EBIT or EBITDA basis for the interest limitation after OBBBA?
“EBIT basis. The EBITDA add-back only applied before 2022.”
“EBITDA basis, permanent. OBBBA §70303(a) struck the 2022 cutoff.”
What is the 2026 Form 1099 reporting threshold?
“$1,000 for 2026,” then “corrected” itself to the same wrong number.
“$2,000, raised by OBBBA §70433(a).”
What bonus depreciation rate applies to equipment acquired in mid-2025?
“40% bonus for 2025. Pending legislation could restore 100%.”
“100%, permanent. OBBBA §70301; Notice 2026-11.”
1 Independent benchmark across a stratified set of U.S. federal tax questions (single run), each answered by the same leading AI model with and without taxmcp.io and graded against primary authority. Mean grader score 0–10; ranges are standard error across questions.
How It Works
Connect taxmcp.io to your AI assistant, then ask tax questions the way you normally would. Every result includes a source link you can inspect.
Add taxmcp.io to Claude Desktop, ChatGPT, or your preferred AI tool. One URL, under two minutes, and you're researching.
Ask tax questions in plain English. “What are the QBI deduction requirements?” “Show me §199A.” Your AI searches the actual IRC, regs, and rulings.
Every result includes the exact section number, source URL, and cross-references—details you can verify and share with clients.
Features
Pull the full text of any U.S. Tax Court opinion by citation or case name (49,000+ opinions back to 1942) and gauge how influential one is with a citation graph built from 500,000+ links between opinions.
Ask questions the way you think about them. “Can my client deduct home office expenses?” returns the exact IRC sections, regs, and rulings that answer it.
Every retrieved result identifies the section or authority and includes a source link you can inspect. Your AI can still make mistakes in its analysis; the underlying reference is there for you to verify.
See how sections connect. When you look up §199A, instantly find every regulation, ruling, and related code section that references it, and everything it references.
Internal Revenue Code, Treasury Regulations, 29 IRS Publications, IRS Notices from 2003–present, and Revenue Rulings and Revenue Procedures from 2019–present, plus 49,000+ U.S. Tax Court opinions on Pro+. All searchable from one place.
Our system checks official government sources regularly for changes, so the index can be refreshed as the law changes.
Connects to Claude Desktop, ChatGPT, and other AI tools. Your AI assistant gets real tax research capabilities built right in.
Who It's For
Research client positions faster with cited IRC sections, regs, and rulings, right inside your AI assistant.
Professional-grade tax research without the enterprise price tag. Free to start, scales with your practice.
Every answer links to authoritative government sources you can verify and cite in memos and opinions.
Pricing
Free for individual practitioners. Upgrade for unlimited federal research, or add Tax Court case law and state tax codes with Pro+.
Free
For individual CPAs, EAs, and tax professionals getting started with AI research.
Pro
Unlimited access to every federal tax source. For practitioners who need comprehensive research.
Pro+
For practices that need case law and multi-state coverage. Adds Tax Court opinions and state tax codes on top of everything in Pro.
State Coverage
State tax code research is included with Pro+. Maine, Oregon, Rhode Island, South Carolina, and Wisconsin are the newest additions, with more coverage rolling out through 2026.
+ 22 more jurisdictions on the roadmap
Need a state that’s not listed? Let us know →Free Claude Skill
A free SKILL.md that turns Claude into a citation-grounded tax researcher – every answer tied to the IRC, Treasury Regs, IRS rulings, and Tax Court. Drop it into Claude Code or the Claude apps.
Get the SkillConnect taxmcp.io to your AI assistant and research from the underlying tax authority. Free to start; setup takes under two minutes.
FAQ
Yes, on the Pro+ plan. taxmcp.io indexes 49,000+ United States Tax Court opinions dating back to 1942, both regular (T.C.) and memorandum (T.C. Memo.) decisions. You can pull the full text of an opinion by citation or case name, then check its citation history against a graph of 500,000+ links between opinions to see how often it has been cited since. This reflects citation activity, not a Shepard’s-style validity check, so always confirm an opinion is still good law before relying on it.
taxmcp.io indexes five core federal tax source types: the full Internal Revenue Code (Title 26), Treasury Regulations, 29 IRS Publications, IRS Notices from 2003 to present, and Revenue Rulings and Revenue Procedures from 2019 to present. The Pro+ plan adds 49,000+ United States Tax Court opinions (case law dating back to 1942) and state tax codes. All sources are searchable from a single query.
Legacy platforms like Thomson Reuters Checkpoint and CCH IntelliConnect charge thousands per seat per year for web portal access, and their AI layers like CoCounsel Tax sit on top of those subscriptions. taxmcp.io starts free, is $9/month for unlimited federal research, and $29/month with Tax Court case law and state tax codes included. It works inside the AI tools you already use (Claude, ChatGPT) and every result links directly to authoritative government sources.
Yes. taxmcp.io provides an MCP server that connects to Claude and ChatGPT through their connector settings. It also works with other MCP-compatible clients.
Not yet. We're focused on delivering the best MCP experience first. A REST API is on our roadmap. If you have a specific use case, reach out and we'll keep you posted.
Our system checks official government sources regularly for changes. Before relying on an authority, confirm its effective date and version against the linked source.
The free plan includes 20 searches per day with access to the Internal Revenue Code. It works with Claude Desktop and ChatGPT, and results include links to the underlying sources. Upgrade to Pro ($9/month) for unlimited searches across all five federal source types, or Pro+ ($29/month) to add Tax Court case law and state tax codes.
From the Blog
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